1921553 has 2 divisors, whose sum is σ = 1921554. Its totient is φ = 1921552.

The previous prime is 1921537. The next prime is 1921559. The reversal of 1921553 is 3551291.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1227664 + 693889 = 1108^2 + 833^2 .

It is an emirp because it is prime and its reverse (3551291) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1921553 - 2⁴ = 1921537 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1921559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 960776 + 960777.

It is an arithmetic number, because the mean of its divisors is an integer number (960777).

2^1921553 is an apocalyptic number.

It is an amenable number.

1921553 is a deficient number, since it is larger than the sum of its proper divisors (1).

1921553 is an equidigital number, since it uses as much as digits as its factorization.

1921553 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1350, while the sum is 26.

The square root of 1921553 is about 1386.2009233874. The cubic root of 1921553 is about 124.3228018466.

The spelling of 1921553 in words is "one million, nine hundred twenty-one thousand, five hundred fifty-three".